Neptune, at about 165 Earth years.
Jupiter takes 11.86 Earth years to orbit the Sun - this is the 4th longest orbital period.
Neptune has the longest orbital period, which is equal to 59,800 Earth days. Pluto's is even longer (90,588 Earth days), but it has since been reclassified as a dwarf planet.
Uranus has the longest day of any planet in the solar system, with a rotation period of about 17 hours and 14 minutes.
The orbital period of a planet can be calculated using Kepler's third law: P^2 = a^3 where P is the orbital period in years and a is the semi-major axis in astronomical units. For a planet with an average distance of 10 au, its orbital period would be approximately 31.6 years.
Neptune, the eighth planet from the Sun, has the longest period of revolution among the gas giants in our solar system. It takes approximately 165 Earth years to complete one orbit around the Sun. This extensive orbital period is due to its great distance from the Sun compared to the other gas giants.
If you still consider Pluto to be a planet, then the answer is Pluto, which completes one revolution around the sun in 248 years. If you agree with the downgrading of Pluto to something less than a full-fledged planet, then the answer is Neptune. The general rule is: The farther a planet is from the sun on the average, the longer it takes to complete its orbital revolution.
From a star's orbital period, we can infer its distance from the object it is orbiting (based on Kepler's third law), the system's total mass (by combining other observable parameters), and potentially the star's luminosity and size if additional information is available. The orbital period can also give insights into the stability of the system and the potential presence of other planets or companions.
Each planet in the solar system has a different orbital period, corresponding to the different sizes of their elliptical orbits.For the Earth, the present orbital period is 365.25636days. (rounded)
In a two-planet system, when one planet is closest to its star and moving fastest (maximized velocity), the other planet is farthest away and moving slowest. This can affect the period of the two planets in their orbits, potentially leading to variations in their orbital time intervals.
The planet with the longest orbit in our solar system is Neptune. It takes approximately 165 Earth years to complete one orbit around the Sun. This extended orbital period is due to its great distance from the Sun, located about 30 astronomical units away. Consequently, Neptune's last complete orbit was finished in 2011, after being discovered in 1846.
In our solar system Neptune is the planet with the longest period or year - equal to about 165 Earth years.
Mercury has the 2nd longest "sidereal day" with a sidereal rotation period of 58.646 Earth days. The longest "sidereal day" day is Venus, with a sidereal rotation period of 243.018 Earth daysIf you use the "solar day" as your definition of "day", the order is reversed. Mercury then has the longest day and Venus has the second longest day.